US20060113856A1 - Axial air-gap electronic motor - Google Patents

Axial air-gap electronic motor Download PDF

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Publication number
US20060113856A1
US20060113856A1 US11/284,935 US28493505A US2006113856A1 US 20060113856 A1 US20060113856 A1 US 20060113856A1 US 28493505 A US28493505 A US 28493505A US 2006113856 A1 US2006113856 A1 US 2006113856A1
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Prior art keywords
rotor
magnet
axial air
electronic motor
provided
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US11/284,935
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US7629724B2 (en
Inventor
Toshiaki Tanno
Tomonori Kojima
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Fujitsu General Ltd
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Fujitsu General Ltd
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Priority to JP2004341905A priority patent/JP4687871B2/en
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Assigned to FUJITSU GENERAL LIMITED reassignment FUJITSU GENERAL LIMITED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TANNO, TOSHIAKI, KOJIMA, TOMONORI
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K21/00Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/24Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets axially facing the armatures, e.g. hub-type cycle dynamos
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K1/00Details of the magnetic circuit
    • H02K1/06Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22Rotating parts of the magnetic circuit
    • H02K1/27Rotor cores with permanent magnets
    • H02K1/2793Rotor axially facing stator

Abstract

There is provided, at a low cost, an axial air-gap electronic motor capable of preventing a magnet from coming off and carrying out position detection more surely. In an axial air-gap electronic motor in which the teeth surface of a stator and the magnet surface of a rotor are arranged opposedly with a predetermined gap being provided therebetween along the axis line direction of the output shaft of the rotor, the rotor has a rotor back yoke arranged coaxially with the stator and a rotor magnet installed to the rotor back yoke so as to face to the teeth surface of the stator, and the rotor magnet is provided with an anchor magnet which is integral with the rotor magnet and is arranged on the back surface side of the rotor back yoke.
The anchor magnet 36 integral with the rotor magnet 32 via a through hole 35 is provided on the back surface side of the rotor back yoke 31 of the rotor 3, thereby fixing the rotor magnet 32, and further position detection is carried out by the anchor magnet 36.

Description

    TECHNICAL FIELD
  • The present invention relates to an axial air-gap electronic motor in which a rotor and a stator are opposedly arranged along the axial direction of a rotor output shaft. More particularly, it relates to an axial air-gap electronic motor in which a rotor magnet can be fixed surely to a rotor back yoke.
  • BACKGROUND ART
  • For example, as shown in Patent Document 1 (Japanese Patent Application Publication No. H03-212141), an axial air-gap electronic motor is a motor in which a rotor is arranged opposedly on one side surface or both side surfaces of a stator with a predetermined gap being provided therebetween, and is characterized in that the thickness thereof in the rotating shaft direction can be decreased, namely, the motor can be made flat as compared with a radial air-gap electronic motor such as an inner rotor type.
  • Usually, the rotor consists of a rotor back yoke formed by a disc-shaped body and a rotor magnet attached integrally to the surface of the rotor back yoke, which faces to the stator, and the rotor magnet is attached integrally to the rotor back yoke with an adhesive or the like.
  • Also, a brushless motor including the axial air-gap electronic motor is provided with rotation position detecting means for detecting the rotation position (rotation phase) thereof. As one example, in Patent Document 2 (Japanese Patent Application Publication No. S63-92250), a position detecting magnet is provided on the outer peripheral surface of the rotor, and also a position detecting sensor is provided around the rotor.
  • Also, as another method, Patent Document 2 has disclosed a technique in which the position detecting sensor is installed on the back surface side of the rotor back yoke to carry out position detection (sensing). Further, as still another method, Patent Document 3 (Japanese Patent Application Publication No. S62-189960) has proposed a brushless motor in which the position detecting sensor is arranged in the coil of the stator.
  • However, the conventional axial air-gap electronic motor has problems as described below. For the axial air-gap electronic motor, the rotor is attracted to the stator side by the magnetic attraction force of the coil at the time of operation. Therefore, if the rotor magnet is fixed merely by bonding as described in Patent Document 1, the rotor magnet may peel off. The rate of occurrence of this peeling-off phenomenon increases as the motor torque becomes high.
  • Also, in the method described in Patent Document 2, the magnet and attachment member used exclusively for position detection are required, so that not only the manufacturing cost increases accordingly but also the weight of the rotor itself increases because of the additional installation of the detecting magnet, thereby increasing electric power consumption.
  • Also, in the case where the position detecting sensor is installed on the back surface side of the rotor, a communication hole is formed to obtain a magnetic gap in a part of the rotor back yoke. In the hole forming process, the position of the communication hole varies easily, and also it is difficult to perform highly accurate sensing because the distance between the magnet and the position detecting sensor becomes long.
  • Further, in the case where the position detecting sensor is installed on the stator side as shown in Patent Document 3, there also arises a problem in that the position detecting sensor is easily affected by a magnetic field generated by the stator, so that exact position sensing cannot be performed.
  • SUMMARY OF THE INVENTION
  • Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide, at a low cost, an axial air-gap electronic motor capable of preventing a magnet from coming off and carrying out position detection more surely.
  • To achieve the above object, the present invention has some features as described below. First, in an axial air-gap electronic motor in which the teeth surface of a stator and the magnet surface of a rotor are arranged opposedly with a predetermined gap being provided therebetween along the axis line direction of the output shaft of the rotor, the rotor has a rotor back yoke arranged coaxially with the stator and a rotor magnet installed to the rotor back yoke so as to face to the teeth surface of the stator, and the rotor magnet is provided with an anchor magnet which is integral with the rotor magnet and is arranged on the back surface side of the rotor back yoke.
  • According to this configuration, the anchor magnet formed integrally with the rotor magnet is provided on the back surface side of the rotor magnet, by which the coming-off of the rotor magnet can be prevented easily and surely.
  • The rotor magnet is formed of a moldable magnet material, and is integrally formed with the anchor magnet via a through hole passing through the rotor back yoke in the axial direction. Alternatively, the rotor magnet is integrally formed with the anchor magnet via the outer periphery of the rotor back yoke. Preferably, at the outer periphery of the rotor back yoke, a notch portion in which the anchor magnet is formed is provided.
  • According to this configuration, the rotor magnet and the anchor magnet are integrally molded in a part of the rotor back yoke via the through hole (or the outer periphery), by which the coming-off of the rotor magnet can be prevented surely by the magnetic attraction force.
  • Also, the through hole or the notch portion is preferably provided for each magnetic pole of the rotor magnet.
  • According to this configuration, the through hole or the notch portion is provided for each magnetic pole, by which a force applied to the rotor magnet can be distributed effectively, and the coming-off can be prevented more surely. Also, this configuration is suitable for sensing.
  • Further, it is preferable that the through hole be provided at least at two locations for each magnetic pole of the rotor magnet, and the anchor magnet be formed as one pattern so as to cover the through holes.
  • According to this configuration, two through holes are provided, and the anchor magnet is formed as one pattern so as to cover the through holes, by which not only the rotor magnet can surely be prevented from coming off but also highly accurate sensing can be performed.
  • A position detecting sensor for detecting the position of the rotor is further provided, and the position detecting sensor is provided at a position facing to the rotation path of the anchor magnet.
  • According to the invention described in claim 7, the position detecting sensor is provided at a position facing to the rotation path of the anchor magnet, by which the rotation position can be sensed surely and accurately by utilizing the anchor magnet that is a part of the rotor magnet.
  • It is preferable that the rotor magnet consist of a plurality of magnet members divided for each magnetic pole, and the magnet members be arranged in a ring shape with the rotation axis line being the center.
  • According to this configuration, the rotor magnet is arranged by being divided for each magnetic pole, by which a crack of the rotor magnet generated by a difference in linear expansion coefficient between the rotor back yoke and the rotor magnet can be prevented effectively.
  • Also, it is preferable that the stator consist of a plurality of core members divided for each teeth, and the core members be arranged in a ring shape with the rotation axis line being the center.
  • According to this configuration, the stator core is formed by arranging the plurality of core members in a ring shape with the rotation axis line being the center, by which the assembling work can be performed easily, and hence the motor can be manufactured at a lower cost.
  • Further, the rotor magnet is preferably polarized in the thrust direction. According this configuration, since the magnet is polarized in the vertical direction with respect to the back yoke surface, the orientation of magnet can be determined by scarcely being subject to the magnetic influence of the rotor back yoke surface. As a result, the magnet can be polarized surely.
  • The rotor magnet is preferably formed so that the thickness thereof is small at both ends in the rotation direction for each magnetic pole, and the thickness thereof in the central portion is larger than that at both ends in the circumferential direction. According to this configuration, by increasing the thickness in the central portion, the magnetic flux density waveform produced by the rotor magnet can be brought close to a sinusoidal wave, so that noise and vibration at the time of operation can be reduced.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is an exploded perspective view of an axial air-gap electronic motor in accordance with a first embodiment of the present invention;
  • FIG. 2 is a longitudinal sectional view of the axial air-gap electronic motor of the first embodiment shown in FIG. 1;
  • FIG. 3 is a front view of a stator of the axial air-gap electronic motor of the first embodiment shown in FIG. 1;
  • FIG. 4A is a front view of a rotor of the axial air-gap electronic motor of the first embodiment shown in FIG. 1;
  • FIG. 4B is a back view of the rotor shown in FIG. 4A;
  • FIG. 4C is a sectional view taken along the line A-A of FIG. 4B;
  • FIGS. 5A to 5D are front views showing various modifications of the
  • FIG. 6 is a longitudinal sectional view of an axial air-gap electronic motor in accordance with a second embodiment of the present invention;
  • FIG. 7A is a front view of a rotor of the axial air-gap electronic motor of the second embodiment shown in FIG. 6;
  • FIG. 7B is a back view of the rotor shown in FIG. 7A;
  • FIG. 7C is a sectional view taken along the line A-A of FIG. 7B;
  • FIG. 8 is a longitudinal sectional view showing a modification of the second embodiment; and
  • FIGS. 9A to 9E are explanatory views illustrating various modifications of a rotor magnet.
  • DETAILED DESCRIPTION
  • Embodiments of the present invention will now be described with reference to the accompanying drawings. The present invention is not limited to these embodiments. FIG. 1 is an exploded perspective view of an axial air-gap electronic motor in accordance with a first embodiment of the present invention, and FIG. 2 is a central longitudinal sectional view of the first embodiment. FIG. 3 is a front view of a stator, and FIGS. 4A to 4C are a front view, a back view, and an A-A sectional view, respectively, of a rotor of the first embodiment.
  • This axial air-gap electronic motor 1 includes a stator 2 formed into a disc-shape and a pair of rotors 3 arranged opposedly on both side surfaces of the stator 2 with a predetermined gap being provided therebetween. The rotors 3 are fixed coaxially on a rotor output shaft 4 for developing a rotation driving force.
  • The stator 2 and the rotors 3 are housed in a cylindrical housing 10. In this example, at both ends of the housing 10, disc-shaped lid members 10 a and 10 b are provided as shown in FIG. 2, and therein is contained motor mechanism sections.
  • As shown in FIG. 3, the stator 2 includes a plurality of (nine in this example) pole members 21 a to 21 i arranged annularly with the rotation axis line being the center axis. Since each of the pole members 21 a to 21 i has the same construction, in this example, explanation is given by taking the pole member 21 a as an example.
  • The pole member 21 a is formed by winding a coil 24 (refer to FIG. 2) around a bobbin having a pair of, right and left, flange-shaped teeth surfaces 22, and the bobbin is formed by laminating magnetic steel sheets, each of which is formed into an H shape, along the radial direction.
  • Each of the pole members 21 a to 21 i is covered with an insulator (not shown), which is formed of an insulating resin, as a whole with the teeth surfaces 22 being left. This insulator is provided with connecting means, not shown, for connecting the pole members 21 a to 21 i to each other, so that the pole members 21 a to 21 i are connected in a ring shape via this connecting means.
  • The pole members 21 a to 21 i are connected in a ring shape with the axis line being the center by the connecting means, and thereafter are stiffened with a resin by insert molding, by which the stator 2 is assembled. In this example, the synthetic resin that fixes the outer periphery of the stator 2 also serves as the housing 10.
  • Referring again to FIG. 2, a bearing section 23 is arranged in a central portion of the stator 2. In this example, the bearing section 23 has a pair of radial ball bearings 231 and 232, the inner race thereof being press fitted on the rotor output shaft 4, and the outer race thereof being embedded by the synthetic resin material. In the present invention, the construction of the bearing section 23 may be arbitrary.
  • In this example, the rotors 3 have the same rotor output shaft 4 in common. However, a two output shaft type having a rotor output shaft for each rotor 3 may be used. Further, a shaft-less type may be used in which the rotors 3 are supported directly on the stator 2 via a radial ball bearing without using the rotor output shaft 4.
  • Next, the rotors 3 are explained. Since each of the rotors 3 has the same construction, in this example, explanation is given by taking one of the rotors 3 as an example. In this example, the surface on the side facing to the teeth surface 22 of the stator 2 is called the front surface of the rotor 3.
  • As shown in FIG. 4A, the rotor 3 is made up of a rotor back yoke 31 consisting of a disc body arranged coaxially with the stator 2 and a rotor magnet installed integrally with the rotor back yoke 31.
  • In this example, the rotor magnet 32 is formed of a moldable magnet material (for example, Sm—Fe—Ne based bonded magnet) so as to be divided into eight segments. It is preferable that the rotor magnet 32 be polarized in the thrust direction. However, it may be polarized so as to have pole anisotropy.
  • The rotor back yoke 31 is formed of a magnetic material such as an electrolytic zinc-coated carbon steel sheet, and is provided with a shaft fixing hole 33, which is press fixed on the rotor output shaft 4, at the center. Further, the rotor back yoke 31 is provided with a plurality of punched holes 34, which are arranged annularly with the shaft fixing hole 33 being the center, to reduce the weight of the rotor back yoke 31 and to improve the vibration-proofing properties.
  • In this example, the number of the punched holes 34 is eight, and each of the punched holes 34 is formed into a fan shape. However, the punched hole 34 may take any shape other than the fan shape, and the size and the number thereof can be changed arbitrarily according to the specifications of the motor.
  • The rotor back yoke 31 is provided with through holes 35 for integrally fixing the rotor magnet 32. Each of the through holes 35 is a hole passing through the rotor back yoke 31 in the axial direction (the direction perpendicular to the paper surface in FIG. 4A), and the through holes 35 are arranged annularly with the axis line of the rotor output shaft 4 being the center. In this example, a total of sixteen through holes 35 are provided in such a manner that two through holes form a set for each segment of the rotor magnet 32 to prevent the rotation of each segment.
  • The shaft fixing hole 33 and the punched holes 34 can also be used as guide holes in a mold of an insert molding machine when the rotor magnet 32 is insert molded. Specifically, first, the center position is fixed by utilizing the shaft fixing hole 33 at the center, and then the punched holes 34 are fitted on guide ribs provided in the mold, by which the circumferential positioning is performed, so that the positioning can be performed surely. Further, if the through holes 35 are arranged so as to match the gate position of mold, the resin can spread smoothly in the mold, so that the molding work can be performed more easily.
  • The rotor magnet 32 is made up of magnet members 32 a to 32 h of eight segments as described above. Since each of the magnet members 32 a to 32 h has the same construction, explanation is given by taking one magnet member 32 a as an example.
  • The magnet member 32 a is formed substantially into a fan shape having a magnet surface parallel to the teeth surface 22 of the stator 2. The magnet member 32 a is formed integrally with the rotor back yoke 31 by what is called an insert molding technique in which the rotor back yoke 31 is put into a predetermined mold and a resin is poured into the mold.
  • As shown in FIG. 4B, on the back surface side of the rotor back yoke 31, an anchor magnet 36, which is integral with the magnet member 32 a via the through holes 35, is formed. The anchor magnet 36 is formed into an elliptical shape as one pattern so as to cover the through holes 35. The anchor magnet 36 is formed at eight locations in total for each segment of the rotor magnet 32 a to 32 h.
  • The anchor magnet 36 plays both of a role in preventing the magnet member 32 a from coming off at the time of operation and a role as a detecting magnet serving as a detected portion of a position detecting sensor 51 mounted on a circuit board 5, described later.
  • In this example, the anchor magnet 36 is formed as one pattern so as to cover the two through holes 35. However, for example, as shown in FIG. 5A, one anchor magnet 36 a may be formed for one through hole 35 a. By doing this as well, the magnet member 32 a can surely be prevented from coming off. In this case, to prevent the rotation of each segment, the shape of the through hole 35 is preferably elliptical or polygonal.
  • Also, in this example, the through holes 35 a, 35 are provided in the circumferential direction. However, as shown in FIG. 5B, the through holes 35 b may be provided in the radial direction, and anchor magnets 36 b may be provided there. Further, the anchor magnet 36 b may be formed so as to cover a portion between the through holes 35 b as shown in FIG. 4B.
  • In this example, the through holes 35 b are provided at two locations along the circumferential direction (FIG. 4 and FIG. 5A) or along the radial direction (FIG. 5B). However, more through holes 35 a, 35 b may be provided. Specifically, as shown in FIG. 5C, the rotor back yoke 31 is provided with three through holes 35 c to 35 e for one segment, and an anchor magnet 36 c is formed for each of the through holes 35 c to 35 e.
  • In this example, the through holes 35 c to 35 e are arranged so as to connect vertexes of a regular triangle, and these sets of through holes 35 c to 35 e in each segment are arranged annularly. In this example, the anchor magnet 36 c is formed for each of the through holes 35 c to 35 e. However, as shown in FIG. 5D, an anchor magnet 36 d may be formed independently for one through hole 35 c, and an anchor magnet 36 e of one pattern may be formed so as to cover the remaining through holes 35 d and 35 e. According to this configuration, the magnet member can be fixed more firmly. In addition, if the anchor magnet 36 e on the outer periphery side is utilized for detecting position, the influence (ratio) of detection error with respect to variations caused by part accuracy etc. can be reduced, so that stable position detection can be carried out.
  • As shown in FIGS. 5A and 5C, in the case where the anchor magnet 36 a, 36 c is provided independently, even-numbered or odd-numbered anchor magnet 36 a, 36 c has only to be specified and to be detected by the position detecting sensor 51.
  • That is to say, for the adjacent anchor magnets of the same pole, the same pole is detected. Since a place where magnet is absent therebetween is neglected, position detection for each pole can be carried out. However, in the case where strong magnets are used, a place between the magnets may be judged to be a different pole, so that the place should preferably be formed so as to be covered integrally.
  • Referring again to FIGS. 1 and 2, on the anti-stator side of one rotor 3 (left-hand side in FIG. 2), there is arranged the circuit board 5 for controlling the operation of the axial air-gap electronic motor 1. The circuit board 5 consists of a disc body inserted along the inside diameter of the housing 10, and on the mounting surface thereof, various electronic parts (not shown) are mounted.
  • As shown in FIG. 2, on the surface facing to the rotor 3 of the circuit board 5, the position detecting sensor 51 for detecting the rotation position of the rotor 3 is mounted. The position detecting sensor 51 consists of a sensor for detecting magnetic variations, such as a Hall sensor, and is arranged relatively on the rotation path of the anchor magnet 36 of the rotor 3.
  • According to this configuration, not only the rotation of the rotor 3 can be detected easily but also the rotation position of the rotor 3 can be detected immediately from the anchor magnets 36 installed on the rotor 3, so that more accurate position detection can be carried out.
  • Next, an axial air-gap electronic motor in accordance with a second embodiment of the present invention will be described. In the explanation below, the same reference characters are applied to elements that are the same or regarded as the same as those in the first embodiment, and the explanation thereof is omitted.
  • In the second embodiment, since the stator of the axial air-gap electronic motor 1 a is the same as that in the above-described first embodiment, only a rotor is shown. FIG. 6 is a sectional view of an axial air-gap electronic motor in accordance with the second embodiment of the present invention, and FIGS. 7A to 7C are a front view, a back view, and a B-B sectional view, respectively, of a rotor of the second embodiment.
  • As shown in FIG. 7A, the rotor magnet 32 of the second embodiment is formed into a doughnut shape integrally with one surface (the near side of paper surface in FIG. 7A) of the rotor back yoke 31. The rotor magnet 32 may be formed so as to be divided into segments as in the first embodiment.
  • The rotor 3 of the second embodiment has the rotor back yoke 31 formed into a disc shape and the rotor magnet 32 installed integrally with the rotor back yoke 31, and the rotor magnet 32 is fixed so that a part thereof is exposed to the outer periphery side of the rotor back yoke 31.
  • In the second embodiment as well, as shown in FIG. 7B, the rotor back yoke 31 is provided with the shaft fixing hole 33 at the center thereof, and the plurality of punched holes 34 are arranged annularly at the outer periphery of the shaft fixing hole 33. Further, at the outer periphery of the punched holes 34, the plurality of through holes 35 are arranged annularly at predetermined intervals.
  • The rotor back yoke 31 is further formed with eight notch grooves 37 at 45° intervals at the outer peripheral edge thereof. As shown in FIG. 7C, the notch groove 37 consists of a concave groove formed from the outer peripheral edge of the rotor back yoke 31 toward the center thereof.
  • In this example, a part of the rotor magnet 32 is provided with an anchor magnet 36 formed from the side surface side of the rotor back yoke 31 to the back surface side thereof (the near side of paper surface in FIG. 7B) via the notch groove 37 of the rotor back yoke 31 and a second anchor magnet 38 formed through the through hole 35.
  • Coupled with the anchor magnet 36, the position detecting sensor 51 of the circuit board 5 is arranged, as shown in FIG. 6, on the outer periphery side of the rotor 3, namely, on the outer periphery side facing to the anchor magnet 36. According to this configuration, the position detection can be carried out while the rotor magnet 32 is prevented, via the notch portion, from moving in the radial direction and the circumferential direction.
  • In this second embodiment, the position detecting sensor 51 is provided on the outer periphery side. However, for example, as shown in FIG. 8, the position detecting sensor 51 may be provided at a position facing to the back surface side (anti-stator side) of the rotor 3 of the anchor magnet 36 as in the first embodiment.
  • Further, as another method, the position detecting sensor may be provided at a position facing to the second anchor magnet 38. According to this method, a plurality of circuit patterns of circuit board can be prepared, so that the detection position can be changed arbitrarily according to the specifications of the motor.
  • In the above-described embodiment, as shown in FIG. 9A, the rotor magnet 32 and the anchor magnet 36 are connected to each other via the through hole 35 (or the notch groove 37), and both of them are flat bodies having a fixed thickness. However, as shown in FIG. 9B, the anchor magnet 36 may be embedded on the rotor back yoke 31 side. According to this configuration, the whole of the rotor 3 can be formed into a thinner shape.
  • Further, as a preferred mode, it is desirable that the rotor magnet 32 be formed so that the thickness of the outside in the circumferential direction is small and the thickness of the central portion is large. The purpose for this is that the magnetic flux density waveform produced by the rotor magnet is brought close to a sinusoidal wave to reduce noise and vibration at the time of operation.
  • Specifically, as shown in FIG. 9C, a taper surface may be formed on both end sides of the rotor magnet 32 to increase the thickness on the center side. Also, as another method, as shown in FIG. 9D, the taper surface may be formed into an arc shape.
  • Further, as another mode, as shown in FIG. 9E, the configuration may be such that the rotor back yoke 31 is formed with a concave portion, and the rotor magnet 32 is embedded in the concave portion. At this time, the thickness at both ends may be made small and that in the central portion may be made large by forming a taper surface at both ends of the concave portion.
  • In the above-described embodiment, the anchor magnet 36 is formed into a round shape or an elliptical shape. However, the shape and size and the number etc. of the anchor magnet 36 can be changed arbitrarily according to the specifications of the motor if the configuration is such that a part of the rotor magnet 32 is exposed on the back surface side (or the side surface side) by utilizing the through hole 35.
  • Also, in the above-described embodiments, there is used the axial air-gap electronic motor having a configuration in which the teeth surface of stator has nine slots and the number of rotor poles is eight, which is highly efficient in reducing cogging torque. However, a slot and pole configuration other than the above may be applied to an electronic motor having a basic axial air-gap type construction.
  • The present application is based on, and claims priority from, Japanese Application Serial Number JP2004-341905, filed Nov. 26, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety.

Claims (11)

1. An axial air-gap electronic motor in which the teeth surface of a stator and the magnet surface of a rotor are arranged opposedly with a predetermined gap being provided therebetween along the axis line direction of the output shaft of the rotor, wherein
the rotor has a rotor back yoke arranged coaxially with the stator and a rotor magnet installed to the rotor back yoke so as to face to the teeth surface of the stator, and the rotor magnet is provided with an anchor magnet which is integral with the rotor magnet and is arranged on the back surface side of the rotor back yoke.
2. The axial air-gap electronic motor according to claim 1, wherein the rotor magnet is formed of a moldable magnet material, and is integrally formed with the anchor magnet via a through hole passing through the rotor back yoke in the axial direction.
3. The axial air-gap electronic motor according to claim 1, wherein the rotor magnet is formed of a moldable magnet material, and is integrally formed with the anchor magnet via the outer periphery of the rotor back yoke.
4. The axial air-gap electronic motor according to claim 3, wherein at the outer periphery of the rotor back yoke, a notch portion in which the anchor magnet is formed is provided.
5. The axial air-gap electronic motor according to claim 2, wherein the through hole or the notch portion is provided for each magnetic pole of the rotor magnet.
6. The axial air-gap electronic motor according to claim 2, wherein the through hole is provided at least at two locations for each magnetic pole of the rotor magnet, and the anchor magnet is formed as one pattern so as to cover the through holes.
7. The axial air-gap electronic motor according to claim 1, wherein a position detecting sensor for detecting the position of the rotor is further provided, and the position detecting sensor is provided at a position facing to the rotation path of the anchor magnet.
8. The axial air-gap electronic motor according to claim 1, wherein the rotor magnet consists of a plurality of magnet members divided for each magnetic pole, and the magnet members are arranged in a ring shape with the rotation axis line being the center.
9. The axial air-gap electronic motor according to claim 1, wherein the stator consists of a plurality of core members divided for each teeth, and the core members are arranged in a ring shape with the rotation axis line being the center.
10. The axial air-gap electronic motor according to claim 1, wherein the rotor magnet is polarized in the thrust direction.
11. The axial air-gap electronic motor according to any one of claims 1 to 10 claim 1, wherein the rotor magnet is formed so that the thickness thereof is small at both ends in the rotation direction for each magnetic pole, and the thickness thereof in the central portion is larger than that at both ends in the circumferential direction.
US11/284,935 2004-11-26 2005-11-23 Axial air-gap electronic motor Active 2026-07-29 US7629724B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2004-341905 2004-11-26
JP2004341905A JP4687871B2 (en) 2004-11-26 2004-11-26 Axial gap motor

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JP (1) JP4687871B2 (en)
KR (1) KR101127196B1 (en)
CN (1) CN1783648B (en)
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Cited By (16)

* Cited by examiner, † Cited by third party
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US20060244333A1 (en) * 2005-04-29 2006-11-02 Young-Chun Jeung Two-phase brushless DC motor
US20080191562A1 (en) * 2006-11-16 2008-08-14 Tomonori Kojima Axial air gap type electric motor
US20080203831A1 (en) * 2005-04-08 2008-08-28 Andrew Boyd French Magnetic Drive Apparatus
US20080313884A1 (en) * 2007-05-11 2008-12-25 Young-Chun Jeung Method of making rotor of brushless motor
US20080315691A1 (en) * 2007-05-11 2008-12-25 Young-Chun Jeung Rotor of brushless motor
US20090001835A1 (en) * 2006-11-16 2009-01-01 Tomonori Kojima Axial air gap type electric motor
US20090026999A1 (en) * 2007-07-24 2009-01-29 Honda Motor Co., Ltd. Motor controller
NL1035278C2 (en) * 2008-04-10 2009-10-13 Friend Investements Sorl A device for the generation of power.
US20090323208A1 (en) * 2008-06-25 2009-12-31 Hoya Corporation Rotary actuator
US20110095642A1 (en) * 2009-10-22 2011-04-28 Yuji Enomoto Magnetic iron core, method for manufacturing the same, axial-gap rotating electrical machine, and static electrical machine
US20110309726A1 (en) * 2009-02-13 2011-12-22 Isis Innovation Ltd Electric machine- modular
WO2012022974A1 (en) * 2010-08-19 2012-02-23 Oxford Yasa Motors Limited Electric machine - over-moulding construction
US20140175931A1 (en) * 2012-12-21 2014-06-26 Samsung Electro-Mechanics Co., Ltd. Axial flux permanent magnet motor
US9054566B2 (en) 2009-04-14 2015-06-09 Isis Innovation Ltd Electric machine—evaporative cooling
US9071117B2 (en) 2009-02-13 2015-06-30 Isis Innovation Ltd. Electric machine—flux
US9496776B2 (en) 2009-02-13 2016-11-15 Oxford University Innovation Limited Cooled electric machine

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5058034B2 (en) * 2008-03-11 2012-10-24 富士重工業株式会社 General-purpose engines
US7812500B1 (en) * 2008-11-12 2010-10-12 Demetrius Calvin Ham Generator / electric motor
TWI419446B (en) * 2009-09-02 2013-12-11 Delta Electronics Inc Magnetic vibrator
JP5471621B2 (en) * 2010-03-08 2014-04-16 株式会社富士通ゼネラル Axial gap motor
TWI398078B (en) * 2010-06-03 2013-06-01
KR101787755B1 (en) * 2011-04-15 2017-10-18 엘지이노텍 주식회사 Anti-seperating structure of sensing magnet for eps motor
JP6208334B2 (en) * 2014-04-25 2017-10-04 株式会社日立産機システム Axial air gap type rotary electric machine

Citations (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3742243A (en) * 1971-09-27 1973-06-26 Veeder Industries Inc Pulse generator
US4086519A (en) * 1977-02-25 1978-04-25 Electro-Craft Corporation Hall effect shaft angle position encoder
US4329636A (en) * 1978-07-25 1982-05-11 Mitsubishi Denki Kabushiki Kaisha Rotation sensor device
US4455516A (en) * 1981-12-18 1984-06-19 Alps Electric Co., Ltd. Brushless motor
US4701649A (en) * 1985-08-02 1987-10-20 Alps Electric Co., Ltd. Brushless motor with symmetrical leads for preventing signal distortion
US4996457A (en) * 1990-03-28 1991-02-26 The United States Of America As Represented By The United States Department Of Energy Ultra-high speed permanent magnet axial gap alternator with multiple stators
US5218251A (en) * 1991-10-28 1993-06-08 Allwine Jr Elmer C Composite magnet stepper motor
US5233296A (en) * 1989-02-09 1993-08-03 Sony Corporation Floppy disk drive revolution detector avoiding interference with magnetic circuit
US5245238A (en) * 1991-04-30 1993-09-14 Sundstrand Corporation Axial gap dual permanent magnet generator
US5345130A (en) * 1993-04-28 1994-09-06 General Electric Company Modable permanent magnet rotor for optimized field shaping
US5359248A (en) * 1990-10-12 1994-10-25 Seiko Epson Corporation Corrosion resistant rotor with auxiliary yokes
US5440185A (en) * 1991-10-28 1995-08-08 Allwine, Jr.; Elmer C. Composite magnet brushless DC motor
US5637945A (en) * 1992-09-22 1997-06-10 Hitachi, Ltd. Brushless motor
US5783880A (en) * 1992-05-08 1998-07-21 Matsushita Electric Industrial Co., Ltd Motor for driving information medium
US5939809A (en) * 1995-10-04 1999-08-17 Empresa Brasileira De Compressores S/A Embraco Rotor with permanent magnets for an electric motor
US6011337A (en) * 1998-09-15 2000-01-04 Lin; Shou-Mei Double-sided, non-iron core, brushless, axial magnetic field permanent-magnet type DC motor
US6445105B1 (en) * 1999-04-06 2002-09-03 General Electric Company Axial flux machine and method of fabrication
US6476528B2 (en) * 2000-05-26 2002-11-05 Alps Electric Co., Ltd. Spindle motor rotor, index signal output device, and floppy disk drive having the same
US6657328B2 (en) * 2000-10-24 2003-12-02 Kabushiki Kaisha Toshiba Rotor for electric motor and method of making the same
US6762527B1 (en) * 2003-06-19 2004-07-13 Yea Huey Horng DC brushless motor
US20040164641A1 (en) * 2003-02-26 2004-08-26 Fujitsu General Limited Axial gap electronic motor
US20060043821A1 (en) * 2004-08-25 2006-03-02 Fujitsu General Limited Axial air-gap electronic motor

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0119585Y2 (en) * 1982-06-15 1989-06-06
JPS59144352A (en) * 1983-02-01 1984-08-18 Seiko Epson Corp Multipolarly magnetized magnet for rotary electric machine
JPS60102853A (en) * 1983-11-08 1985-06-07 Matsushita Electric Ind Co Ltd Permanent magnet rotor of motor
JPS62135564U (en) * 1986-02-20 1987-08-26
JPS62213540A (en) * 1986-03-14 1987-09-19 Nissan Motor Co Ltd Ac generator
JPS63187583U (en) * 1987-05-19 1988-12-01
JPH08130861A (en) * 1994-09-07 1996-05-21 Tohoku Ricoh Co Ltd Face-to-face dc brushless motor
JP2001054270A (en) * 1999-08-05 2001-02-23 Sankyo Seiki Mfg Co Ltd Counterposed type motor
JP4639632B2 (en) * 2004-04-28 2011-02-23 株式会社エクォス・リサーチ Axial gap motor

Patent Citations (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3742243A (en) * 1971-09-27 1973-06-26 Veeder Industries Inc Pulse generator
US4086519A (en) * 1977-02-25 1978-04-25 Electro-Craft Corporation Hall effect shaft angle position encoder
US4329636A (en) * 1978-07-25 1982-05-11 Mitsubishi Denki Kabushiki Kaisha Rotation sensor device
US4455516A (en) * 1981-12-18 1984-06-19 Alps Electric Co., Ltd. Brushless motor
US4701649A (en) * 1985-08-02 1987-10-20 Alps Electric Co., Ltd. Brushless motor with symmetrical leads for preventing signal distortion
US5233296A (en) * 1989-02-09 1993-08-03 Sony Corporation Floppy disk drive revolution detector avoiding interference with magnetic circuit
US4996457A (en) * 1990-03-28 1991-02-26 The United States Of America As Represented By The United States Department Of Energy Ultra-high speed permanent magnet axial gap alternator with multiple stators
US5359248A (en) * 1990-10-12 1994-10-25 Seiko Epson Corporation Corrosion resistant rotor with auxiliary yokes
US5245238A (en) * 1991-04-30 1993-09-14 Sundstrand Corporation Axial gap dual permanent magnet generator
US5218251A (en) * 1991-10-28 1993-06-08 Allwine Jr Elmer C Composite magnet stepper motor
US5440185A (en) * 1991-10-28 1995-08-08 Allwine, Jr.; Elmer C. Composite magnet brushless DC motor
US5783880A (en) * 1992-05-08 1998-07-21 Matsushita Electric Industrial Co., Ltd Motor for driving information medium
US5637945A (en) * 1992-09-22 1997-06-10 Hitachi, Ltd. Brushless motor
US5345130A (en) * 1993-04-28 1994-09-06 General Electric Company Modable permanent magnet rotor for optimized field shaping
US5939809A (en) * 1995-10-04 1999-08-17 Empresa Brasileira De Compressores S/A Embraco Rotor with permanent magnets for an electric motor
US6011337A (en) * 1998-09-15 2000-01-04 Lin; Shou-Mei Double-sided, non-iron core, brushless, axial magnetic field permanent-magnet type DC motor
US6445105B1 (en) * 1999-04-06 2002-09-03 General Electric Company Axial flux machine and method of fabrication
US6476528B2 (en) * 2000-05-26 2002-11-05 Alps Electric Co., Ltd. Spindle motor rotor, index signal output device, and floppy disk drive having the same
US6657328B2 (en) * 2000-10-24 2003-12-02 Kabushiki Kaisha Toshiba Rotor for electric motor and method of making the same
US20040164641A1 (en) * 2003-02-26 2004-08-26 Fujitsu General Limited Axial gap electronic motor
US6762527B1 (en) * 2003-06-19 2004-07-13 Yea Huey Horng DC brushless motor
US20060043821A1 (en) * 2004-08-25 2006-03-02 Fujitsu General Limited Axial air-gap electronic motor

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080203831A1 (en) * 2005-04-08 2008-08-28 Andrew Boyd French Magnetic Drive Apparatus
US8004141B2 (en) 2005-04-29 2011-08-23 Sntech Inc. Two-phase brushless DC motor
US20060244333A1 (en) * 2005-04-29 2006-11-02 Young-Chun Jeung Two-phase brushless DC motor
US20080191562A1 (en) * 2006-11-16 2008-08-14 Tomonori Kojima Axial air gap type electric motor
US20090001835A1 (en) * 2006-11-16 2009-01-01 Tomonori Kojima Axial air gap type electric motor
US20080315691A1 (en) * 2007-05-11 2008-12-25 Young-Chun Jeung Rotor of brushless motor
US8299661B2 (en) * 2007-05-11 2012-10-30 Sntech Inc. Rotor of brushless motor
US8033007B2 (en) 2007-05-11 2011-10-11 Sntech, Inc. Method of making rotor of brushless motor
US20080313884A1 (en) * 2007-05-11 2008-12-25 Young-Chun Jeung Method of making rotor of brushless motor
US20090026999A1 (en) * 2007-07-24 2009-01-29 Honda Motor Co., Ltd. Motor controller
US7999501B2 (en) * 2007-07-24 2011-08-16 Honda Motor Co., Ltd. Motor controller
NL1035278C2 (en) * 2008-04-10 2009-10-13 Friend Investements Sorl A device for the generation of power.
US20110042961A1 (en) * 2008-04-10 2011-02-24 Brestac Holding BV Device for generating power
CN102089960A (en) * 2008-04-10 2011-06-08 布莱斯泰科控股有限公司 Device for generating power
WO2009126025A1 (en) 2008-04-10 2009-10-15 Friend Investments Sarl Device for generatingpower
US8149520B2 (en) * 2008-06-25 2012-04-03 Pentax Ricoh Imaging Company, Ltd. Rotary actuator for auto-focusing a camera lens
US20090323208A1 (en) * 2008-06-25 2009-12-31 Hoya Corporation Rotary actuator
US20110309726A1 (en) * 2009-02-13 2011-12-22 Isis Innovation Ltd Electric machine- modular
US9318938B2 (en) * 2009-02-13 2016-04-19 Isis Innovation Ltd. Electric machine-modular
US9496776B2 (en) 2009-02-13 2016-11-15 Oxford University Innovation Limited Cooled electric machine
US9071117B2 (en) 2009-02-13 2015-06-30 Isis Innovation Ltd. Electric machine—flux
US9054566B2 (en) 2009-04-14 2015-06-09 Isis Innovation Ltd Electric machine—evaporative cooling
US20110095642A1 (en) * 2009-10-22 2011-04-28 Yuji Enomoto Magnetic iron core, method for manufacturing the same, axial-gap rotating electrical machine, and static electrical machine
US8937422B2 (en) * 2009-10-22 2015-01-20 Hitachi Industrial Equipment Systems Co., Ltd. Magnetic iron core, method for manufacturing the same, axial-gap rotating electrical machine, and static electrical machine
WO2012022974A1 (en) * 2010-08-19 2012-02-23 Oxford Yasa Motors Limited Electric machine - over-moulding construction
US9287755B2 (en) * 2010-08-19 2016-03-15 Yasa Motors Limited Electric machine—over-moulding construction
US20130147291A1 (en) * 2010-08-19 2013-06-13 Oxford Yasa Motors Limited Electric machine - over-moulding construction
US20140175931A1 (en) * 2012-12-21 2014-06-26 Samsung Electro-Mechanics Co., Ltd. Axial flux permanent magnet motor

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